In the fabrication of vinyl chloride resins by calendering, extrusion, die-coating, etc., the resins are first mechanically blended with liquid plasticizers. The particles of resin imbibe the liquid plasticizers substantially completely, so that the granular resin retains its flowable character. This process is called "dry-blending", and it is very desirable that the resins shall be of such character that they will quickly imbibe the plasticizers, so as to minimize the time in the blending equipment. Such desirable resins are referred to as having short "dry-blend" times.
A patent to Nelson et al U.S. Pat. No. 3,706,722 discloses the preparation of plasticizer-absorbent resins by a process in which vinyl chloride is initially polymerized as the external phase to an internal aqueous phase containing sorbitan stearate plus hydroxypropyl methyl cellulose ether. After the initial polymerization, additional aqueous medium is added, causing a phase inversion, and the polymerization is carried to completion. This process is inherently cumbersome and difficult to control.
Accordingly, it is the object of this invention to provide a process for the production of vinyl chloride resins having short dry blend times, without having recourse to the cumbersome phase-reversal process of the prior art.